1. Field of the Invention
The present invention relates to a mobile communication method, a mobile communication system and a radio base station which comply with a scheme of previously securing hardware resources inside a radio base station, the hardware resources intended to be used for decoding uplink signals transmitted from a mobile station.
2. Description of the Related Art
In a mobile communication system employing an enhanced uplink (EUL) scheme, i.e., a high speed uplink packet access (HSUPA) scheme defined in 3GPP, a radio base station (hereinafter, referred to as NodeB as appropriate) is configured to determine which UE to be allowed to transmit uplink user data and to allocate radio resources for the uplink user data transmission to the mobile station at each transmission time interval (TTI). In other words, the NodeB is configured to determine a transmission rate allowed for the uplink user data transmission from the UE (hereinafter, referred to as UE as appropriate).
Then, the NodeB transmits a scheduling grant (hereinafter, referred to as SG) corresponding to the hardware resources allocated to the UE, to the UE via an E-DCH absolute grant channel (E-AGCH) or an E-DCH relative grant channel (E-RGCH). The UE transmits uplink user data to the NodeB at a transmission rate corresponding to the received SG (see, for example, Japanese Patent Translation Publication No. 2007-151146).
However, there is a problem that the NodeB is likely to fail to receive the uplink user data correctly if a difference exists on recognized hardware resources for transmission of the uplink user data, specifically a recognized uplink user data transmittable rate between the NodeB and the UE.